二分查找

二分查找

import java.util.Scanner; public class Test{ public static void main(String[] args) { int [] arr = {1,5,8,10,45,60,79,92}; Scanner myScanner = new Scanner (System.in); System.out.println("请输入您要查找的数"); int num = myScanner.nextInt(); int leftIndex = 0; int rightIndex = arr.length-1; int index = -1; while (leftIndex <= rightIndex){ int middleIndex = (leftIndex+rightIndex) / 2; int middle = arr [middleIndex]; if (num == middle){ System.out.println("恭喜找到下标为"+middleIndex); index = middleIndex; break; }else if (num < middle){ rightIndex = middleIndex - 1; }else { leftIndex = middleIndex + 1; } } if (index == -1){ System.out.println("未找到"); } } }